Quality control of cashew apple and guava nectar by near infrared spectroscopy

Near infrared (NIR) spectroscopy along with multivariate calibration was used for quality control of cashew apple and guava nectars. Total acidity, total sugars, soluble solids, pH, and ascorbic acid contents were analyzed by traditional wet chemical methodologies and NIR. The spectral data were preprocessed with multiplicative scatter correction, mean center and first derivative (Savitsky-Golay). The models presented adequate standard errors of calibration (root mean square error of calibration - RMSEC) and prediction (root mean square error of prediction - RMSEP), respectively, to cashew apple nectar (acidity = 0.022% and 0.025%, total sugars = 0.58% and 0.60%, pH = 0.068 and 0.123, ascorbic acid = 4.61 mg/100 g and 4.80 mg/100 g), and to guava nectar (acidity = 0.019% and 0.024%, total sugars = 0.297% and 0.315%, soluble solids = 0.242 and 0.301 degrees Brix, pH = 0.063 and 0.107, ascorbic acid = 6.41 mg/100 g and 7.44 mg/100 g). Results showed that replacement of traditional methodology by NIR can be viable and recommended since it is a fast, green, easy-to-handle, safe technique, able to process many samples, and parameters in a short time. (C) 2016 Elsevier Inc. All rights reserved.